Open-type hose clamps are known in the prior art which include one or more hook members extending outwardly from the inner band portion and adapted to engage in corresponding apertures in the outer band portion.
These prior art mechanical connections for open-type hose clamps usually include a rectangularly shaped hook member extending outwardly from the inner band portion into a rectangularly shaped aperture provided in the outer band portion as shown, for example, in U.S. Pat. No. 3,321,811 to Thomas. The hook members described above are usually bent out of the band material through an angle less than 90° to act as “guide” members by causing the overlapping band portion to be drawn inwardly toward the inner band portion during tightening of the clamp. Reopening of the mechanical connection of the clamp is likely when such guide members are bent to a 90° position and there beyond during tightening of the clamp.
The apertures in the outer band portion are thereby relatively long to permit movement of the guide hook members in the circumferential direction of the clamp and are much greater than the thickness of the clamping band material which normally consists of galvanized steel or stainless steel band material. Owing to the limited resistance of these hook members causing them to bend back during the tightening of the clamp, there always exists then the resulting danger of unwanted reopening of these open-type hose clamps during the installation of the clamp over the object to be fastened thereby.
There are two usual methods of installing these open-type hose clamps, that is, axially and radially over the object to be fastened thereby. To be able to install these open-type clamps axially, the mechanical connection interconnecting the overlapping band portions must stay closed, i.e., the hook member(s) constituting the mechanical connection must stay engaged in the aperture(s) of the mechanical connection. However, there is always the problem of inadvertent reopening as a result of bending back of the hook member(s), especially also during such axial installation because the clamps are made from flat steel band material and are normally predeformed into more-or-less circular shape, thereby leaving a residual stress in the thus predeformed band material which seeks to return to the prior flat shape. The prior art mechanical connections as used heretofore with the use of at least one of such guide hooks of the type described above provides no assurance against reopening.
When installing the clamp radially over the object to be fastened thereby, it is again necessary that the mechanical connection remain engaged during the entire tightening operation of the clamp. The prior art mechanical connections of the type described above do not provide the necessary assurance to remain engaged.
It is therefore an object of the present invention to provide a mechanical connection in the overlapping band portions of so-called open-type hose clamps which assures that the mechanical connection remains engaged from initial installation throughout the entire tightening operation of the clamp.
Another object of the present invention resides in a mechanical connection for open-type hose clamps which is simple, easy to manufacture and reliable in operation.